The invention relates generally to systems which use and generate images during medical and surgical procedures, which images assist in executing the procedures and indicate the relative position of various body parts and instruments. In particular, the invention relates to a system for generating images during medical and surgical procedures based on a scan taken prior to or during the procedure and based on the present position of the body parts and instruments during the procedure.
Image guided medical and surgical procedures comprise a technology by which scans, obtained either pre-procedurally or intra-procedurally (i.e., prior to or during a medical or surgical procedure), are used to generate images to guide a doctor during the procedure. The recent increase in interest in this field is a direct result of the recent advances in scanning technology, especially in devices using computers to generate three dimensional images of parts of the body, such as computed tomography (CT) or magnetic resonance imaging (MRI).
The majority of the advances in diagrammatic imaging involve devices which tend to be large, encircle the body part being imaged, and are expensive. Although the scans produced by these devices depict the body part under investigation with high resolution and good spatial fidelity, their cost usually precludes the dedication of a unit to be used during the performance of procedures. Therefore, image guided surgery is usually performed using images taken preoperatively.
The reliance upon preoperative images has focused image guidance largely to the cranium. The skull, by encasing the brain, serves as a rigid body which largely inhibits changes in anatomy between imaging and surgery. The skull also provides a relatively easy point of reference to which fiducials or a reference system may be attached so that registration of pre-procedural images to the procedural work space can be done simply at the beginning, during, or throughout the procedure. Registration is defined as the process of relating pre-procedural or intra-procedural scan of the anatomy undergoing surgery to the surgical or medical position of the corresponding anatomy. For example, see Ser. No. 07/909,097, now U.S. Pat. No. 5,383,454 the entire disclosure of which is incorporated herein by reference.
This situation of rigid fixation and absence of anatomical movement between imaging and surgery is unique to the skull and intracranial contents and permits a simple one-to-one registration process as shown in FIG. 1. The position during a medical procedure or surgery is in registration with the pre-procedural image data set because of the absence of anatomical movement from the time of the scan until the time of the procedure; in effect, the skull and it""s intracranial contents comprise a xe2x80x9crigid body,xe2x80x9d that is, an object which does not deform internally. In almost every other part of the body there is ample opportunity for movement within the anatomy which degrades the fidelity by which the pre-procedural scans depict the intra-procedural anatomy. Therefore, additional innovations are needed to bring image guidance to the rest of the body beyond the cranium.
The accuracy of image guided surgery relies upon the ability to generate images during medical and surgical procedures based on scans taken prior to or during the procedure and based on the present position and shape of the body parts during the procedure. Two types of body parts are addressed herein: 1) structures within the body that do not change shape, do not compress, nor deform between the process of imaging and the medical procedure, which are termed xe2x80x9crigid bodies,xe2x80x9d and are exemplified by the bones of the skeleton; and 2) structures within the body that can change shape and deform between the process of imaging and the medical procedure structures are termed xe2x80x9csemi-rigid bodies,xe2x80x9d and are exemplified by the liver or prostate. Both types of body parts are likely targets for medical or surgical procedures either for repair, fusion, resection, biopsy, or radiation treatment. Therefore, a technique is needed whereby registration can be performed between the body parts as depicted pre-procedurally on scans and the position and shape of these same body parts as detected intra-procedurally. This technique mast take into account that movement can occur between portions of the body which are not rigidly joined, such as bones connected by a joint, or fragments of a broken bone, and that shape deformation can occur for semi-rigid bodies, such as the liver or prostate. In particular, the technique must be able to modify the scanned image dataset such that the modified image dataset which is used for localization and display, corresponds to position and/or shape of the body part(s) of interest during a medical or surgical procedure. A key to achieving this correspondence is the ability to precisely detect and track the position and/or shape of the body part(s) of interest during the medical or surgical procedure, as well as to track instruments, xe2x80x94or radiation used during the said procedure.
It is an object of this invention to provide a system which allows registration between a body part depicted in pre-procedural images and tracked during surgery.
It is a further object of this invention to provide a system which allows registration between a semi-rigid body such as the liver depicted in pre-procedural images and detected during surgery.
It is a further object of this invention to provide a system which allows registration between multiple body parts such as skeletal elements depicted in pre-procedural images and detected during surgery.
It is a further object of this invention to provide a system which can localize a semi-rigid body that may deform between imaging and a procedure and provide a display during the procedure of the body in its deformed shape.
It is a further object of this invention to provide a system which can localize multiple rigid bodies that move with respect to each other between imaging and a procedure and provide a display during the procedure of the bodies in their displaced positions.
It is another object of this invention to provide a system for use during a medical or surgical procedure on the body, the system generating a display representing the position of one or more body elements during the procedure based on a scan generated by a scanner either prior to or during the procedure.
It is another object of this invention to provide a system for use during a medical or surgical procedure on a body which modifies the scan taken prior to or during a procedure according to the identified relative position of each of the elements during the procedure.
It is another object of this invention to provide a system for use during a medical or surgical procedure on a body which modifies the image data set according to the identified shape of each of the element during the procedure.
It is another object of this invention to provide a system which generates a display representative of the position of a medical or surgical instrument in relation to the body element(s) during a procedure.
It is a further object of this invention to provide a system for use during image guided medical and surgical procedures which is easily employed by the doctor or surgeon conducting the procedure.
It is another object of this invention to provide a system which determines the relative position and/or shape of body elements during a medical or surgical procedure based on the contour of the body elements which can avoid the need for exposing the body elements.
It is still another object of this invention to provide a system which employs one or more two dimensional fluoroscopic or x-ray images of body elements to determine their relative position and/or shape in three dimensions.
It is yet a further object of this invention to describe a surgical or medical procedure which employs a display representing the position of the body element(s) during the procedure based on an image data set of the body element(s) generated prior to the procedure.
It is a further object of this invention to provide a system and method for medical or surgical procedures which allows repositioning of body elements during the procedure and still permits the generation of a image showing the relative position of the body elements.
It is a further object of this invention to provide a system and method for medical or surgical procedures which allows reshaping of the body element(s) during the procedure and still permits the generation of a image showing the position and current shape of the body elements.
It is a further object of this invention to provide a system which can localize a body element and provide a display during the procedure of the position of the body element relative to an instrument, such as a forceps, microscope, or laser, so that the instrument can be precisely located relative to the body element.
Other objects and features will be in part apparent and in part pointed out hereinafter.
The invention comprises a system for use during a medical or surgical procedure on a patient""s body. The system generates one or more images representing the position and shape of one or more body elements during the procedure using scans generated by a scanner prior to the procedure, the scans having at least one reference point for each of the body elements of interest. These two dimensional scans, taken together, comprise a three dimensional depiction of the body, and are called the image data set. The reference points of a particular body element have a spatial relation to the particular body element. The system includes means for identifying, during the surgical or medical procedure, the position of the reference points of each of the body elements to be displayed by the system. The system also includes a means processor for modifying the image data""set according to the identified position of the reference points of each of the body elements during the medical or surgical procedure, called the identifying means. The processor generates images using a modified (displaced and/or deformed) image data set representing the position and shape of the body elements during the procedure.
Optionally, the processor determines the position of a medical or surgical instrument relative to these body elements. The system also includes a display which utilizes the modified image data set generated by the processor to illustrate the position and shape of the body elements during the procedure and optionally the determined position of the medical or surgical instrument relative to the body elements by means of two dimensional images.
The invention also comprises a method for use during a procedure. The method generates images representing the position and shape of one or more body elements during the procedure based on scans generated prior to the procedure, which scan set has reference points for each of the body elements. The method comprises the steps of:
identifying, during the procedure, the position of the reference points of each of the body, elements to be displayed;
modifying the image data set according to the identified position of the reference points of each body element during the procedure in order to generate a modified (displaced and/or deformed) image data set representing the position of the body elements during the procedure;
optionally determining the position of a medical or surgical instrument, probe or beam of irradiation relative to the body elements; and
generating a display based on the modified image data set illustrating the position and shape of the body elements during the procedure and optionally the position of the medical or surgical instrument relative to the body elements.
The invention also comprises a method for use with two or more body elements each of which have reference points. Prior to the procedure, the method comprises the steps of placing the body elements in a frame to fix their relative position; and scanning the fixed body elements. During the procedure, the method comprises the steps of:
placing the body elements in the frame so that the body elements have the same relative position as their position during scanning;
determining the position of reference points on the body elements relative to reference means;
determining the position of a medical or surgical instrument relative to the reference means;
determining the position of the medical or surgical instrument relative to the body elements; and
generating a display based on the pre-procedural scanning illustrating the determined position of the medical or surgical instrument relative to the body elements.
The invention also comprises a device for use with a surgical navigation system having a sensor array which is in communication with the device to identify its position, the device for use in guiding a catheter, the device for engaging a cable connected to the surgical navigation system, the cable for providing signals for activating the device. A handle has a cavity therein. A plurality of light emitting diodes on the handle emit light, when activated, for communicating with the sensor array of the surgical navigation system. A connector attached to the handle and adapted to engage the cable connected to the surgical navigation system receives the signals for activating the diodes. Wires located in the cavity of the handle and electrically interconnecting the connector and the light emitting diodes transmit the signals received by the connector to the diodes. A guide member connected to the handle guides the catheter.
The invention also comprises a device for use with a surgical navigation system having a sensor array which is in communication with the device to identify its position. A base member has a cavity therein. A plurality of light emitting diodes on the base member emit light, when activated, for communicating with the sensor array of the surgical navigation system. An activating circuit connected to the diodes provides signals for activating the diodes. Wires located in the cavity of the base member and electrically interconnecting the power supply and the light emitting diodes transmit the signals for activating the diodes.
The invention also comprises a device for use with a surgical navigation system having a sensor array which is in communication with the device to identify its position, the device for engaging a structure attached to or an instrument in known relation to a body part thereby providing a known reference relative to the body part, the device having a connector for engaging a cable connected to the surgical navigation system, the cable for providing signals for activating the device. A base member has a cavity therein. A coupling on the base member engages the structure in order to maintain the base member in fixed relation to the body part thereby providing the fixed reference. A plurality of light emitting diodes on the base member, said diodes, when activated, emitting light for communicating with the sensor array of the surgical navigation system. A connector attached to the base member and adapted to engage the cable connected to the surgical navigation system receives the signals for activating the diodes. Wires located in the cavity of the base member and electrically interconnecting the connector and the light emitting diodes transmit the signals received by the connector to the diodes to activate the diodes.
The invention also comprises a device for use with a surgical navigation system having a sensor array which is in communication with the device to identify its position, the device for guiding an instrument for engaging a body part thereby locating the instrument at a known position relative to the body part, the device having a connector for engaging a cable connected to the surgical navigation system, the cable for providing signals for activating the device. A housing has a cavity therein. A structure on the housing guides the instrument in order to maintain the instrument in a relationship relative to the housing. A plurality of light emitting diodes on the housing, when activated, emit light for communicating with the sensor array of the surgical navigation system. A connector attached to the housing and adapted to engage the cable connected to the surgical navigation system receives the signals for activating the diodes. Wires located in the cavity of the housing and electrically interconnecting the connector and the light emitting diodes and for transmitting the signals received by the connector to the diodes to activate the diodes.
In addition, the invention comprises a surgical navigation system comprising:
a calmer;
a sensor array;
a reference frame in communication with the array to identify its position; and
a localization frame in communication with the array to identify a position of the localization frame, the localization frame for guiding the instrument for engaging the body part thereby locating the instrument at a known position relative to the body part, the localization frame connected to the controller which provides signals for activating the localization frame.